Windshield cleaner motor



June 29, 1943.

E. C. HORTON WINDSHIELD CLEANER MOTOR Filed April 2, 1941 v INVENTOREPW/A/ c Am ra/v ATT Patented June 29, 1 943 WINDSHIELD CLEANER MOTORErwin C. Horton, Hamburg,

N. Y., assignor to Trico Products Corporation, Buffalo, N. Y.Application April 2, 1941, Serial No. 386,505 4 Claims. (Cl. 309-22)This invention relates to the-windshield cleaner motor art and moreparticularly to the piston construction and packing of the suction orair operated type in widespread use today. This type of motor comprisesgenerally a segmental shaped motor chamberwith a vane or pistonoperating therein. .Cup leather has frequently been used in the packing'of the piston element of the motor, but owingto the fact that theleather must be skived exceedingly thin in order to have the leatherflanges sufficiently flexible to readily yield to the low pressuredifference obtainable by suction and due to surface irregularities. andinherent defectsfrequently found in hide leather, it has beendiflicultto secure uniformity and commercial'satisfaction in the cup leathers.Furthermore, the leather will absorb some of the lubricant, I which issupplied originally to the piston and motor chamber, and becomechemically affected thereby to impair its 3 proper functioning. Thisfact, coupled with the non-uniformly skived packing, results in a poorlyoperating motor. Again, after long periods of idleness the cup leatherfrequently becomes set and when again placed in operation there is atendency toscore the chamber wall. This is apparent when it isconsidered that the chambers areusually formed of die cast metal whichis soft and easily marked.

The present invention has for its object to provide an improved pistonfor the windshield cleaner motor which will secure greater efllciencyfor the motor. Further, the invention has for its object to provide afabricated packing which will be especially adapted for the die castmetal in that it will slide readily thereover without undue friction.

In the drawing Fig. 1 is a sectional view through a windshield cleanermotor showing the vane or piston in the motor chamber;

Fig. 2 is an enlarged fragmentary view partly in section showing themake-up of the piston; and

Fig. 3 is a detailed fragmentary view of a cup packing member in plan.

Referring more particularly to the drawing, numeral I designates a motorhousing formed of die cast metal and having a semi-round chamber 2 witha shaft 3 journaled concentrically therein for actuating awindshieldwiper carried bythearmlflxedtothe outer endof the shaft 3.Being die cast from this molten metal the molded product has its chamberwall highly polished and smoothly finished Fixed on the shaft within thechamber 2 is a piston of vane construction composed of two sectionsclampingly embracing the shaft therebetween. Each piston sectioncomprises a body plate 5, a cup packing member 6, an expander plate Iand a cap plate 8, all nestingly received or arranged in superimposedrelation and secured together in, a suitable manner with the marginalportions ofthe cup member constituting packing flanges 9 which ride onthe smooth arcuate and side walls of the chamber 2, the side wallengagement extending radially of the chamber and from opposite sides ofthe shaft. The shaft bearing in" the housing I is unpacked and thereforeair leakage along the shaft through its Journal bearings will enter thecompartment I0 between the two piston sections and when suction isapplied to the chamber 2 at one side or the other of the piston apressure differential will result which will urge the packing flanges 9into a leakproof contact with the walls of chamber 2. The expanderplates 1 are of very light shim brass or other light resilient materialdesigned to lightly urge the packing flanges into contact with thechamber walls so that the pressure differential when applied willautomatically seal the piston against air leakage into the chamber 2ahead of the piston. The

cap plate I has its opposite ends conforming in shape to that of thebody plate, being deflected at ll opposite the bend ii in the body plateto serve to shape the packing flanges, as shown in Fig. 2. Thisdeflected margin ll affords proper support for the end packing flangeswhere the travel is greatest.

The cup packing is resistant to lubricant and moisture and comprises afabric base i3 having the warp and woof threads extending substantiallyat right angles to one another and bonded by a plastic body ll of acellulose nitrate plastic sufficiently soft 'to impart to the cuppacking member a flexibility somewhat similar to that of the usual cupleather body. This plasticizer provides an exceedingly smooth outersurface, devoid of crevices or irregularities. The texture is rubberybut, being smooth and finished, will readily slide on the die cast metalwall of the chamber. The inner surface of the cup packing which is alsoproofed against moisture or lubricant may be finished in like manner tothe outer surface, if desired. The paekings are cut from sheet stock andthis exposes the threads of the fabric base at the edges of the flanges.

When the motor is assembled at the factory a quantity of lubricant,generally indicated at it, is inserted in the piston compartment itwhich finds egress therefrom through the space It between the opposededges of the opposing cups. As the motor is continued in use, especiallyin a warm climate, the lubricant will gradually find egress through thespace M between the opposed cups and as it flows over the opposite edgesl1 some of this lubricant will be absorbed or held by the exposedthreads of the fabric base to be released after the lubricant supply hasbeen exhausted. This will tend to prolong the life of the motor bycontinuing its lubrication over a greater period of time and willprevent an earlier undue waste of the lubricant. Likewise, some of thelubricant will be retained between the cup packing and the expanderplate 1 until the main supply has run dry. This is possible because theplastic body M will not absorb the lubricant like the leather packingmember. Consequently the surfaces of the plastic cup member will haveuniform contact with the smooth die cast chamber wall as lubricated bythe grease.

The plastic cup member may have incorporated therein a quantity ofgraphite l8, indicated by the stippling in Fig. 3, the graphite beingincorporated in the plastic body at the time it is applied to the fabricbase Hi. The graphite will manifest its presenceon the surface of thecup packing member in a more or less dull finish, depending upon theamount of graphite employed. With the graphite incorporated thecoefficientof friction is reduced to a minimum and the plastic cuppacking member will slide more readily over the die cast metal wall ofthe chamber so that a smaller quantity of the lubricant IE will berequired.

By the use of the fabricated cup packing uniformity in the cup memberproduct is obtained and therefore uniform motor efliciency results. Forexample, it is possible to hold extremely close dimensional toleranceson the thickness of the fabricated packing within .002 of an inch, plusor minus. The material, being resistant to moisture as well aslubricant, keeps the packing member from swelling and then drying in amisshapen condition. The packing is little aifected by extremetemperature changes and is possessed of a low coefficient of frictionagainst the die cast metal. The result is the uniform production ofeificient motors.

While the foregoing description has been given in detail it isunderstood that the cup packing may be otherwise fabricated, utilizing adifferent plasticizer and a graphite equivalent tending to lower thecoeficient of friction for the exceedingly flexible packing flanges 9which are primarily held in packing fit with the chamber wall by the lowactuating fluid pressure, and therefore it is not the intention tothereby limit the scope except as defined in the appended claims.

What is claimed is:

1. A piston for the suction operated motors ofwindshield cleaners,comprising companion sections embracing a motor shaft therebetween, eachsection embodying a cup packing member with its marginal packing flangesarranged in proximity to the flanges of the companion section, said cupmembers defining a compartment in the piston for the reception of aquantity of lubricant,

the lubricant adapted to'pass out onto the chamber walls across theopposed edges of the marginal packing flanges, said cup packing membersbeing of a material resistant to the lubricant, whereby the escape ofthe lubricant from the compartment is confined solely to the spaceseparating the edges.

2. A piston for the suction operated motors of windshield cleaners,comprising companion sections embracing a motor shaft therebetween, eachsection embodying a soft flexible cup packing.

member with its marginal packing flanges arranged in proximity to theflanges of the companion section, said cup members having its side facesimpervious to lubricant and moisture and defining a compartment in thepiston for the reception of a quantity of lubricant, the lubricantadapted to pass out onto the chamber walls across the opposed edges ofthe marginal packing flanges, said cup packing members beingsufliciently soft to impart to the marginal packing flanges a degree offlexibility for fluid seal contact with the wall of the motor chamber,the cup packing members having exposed lubricant-absorbing portions inthe opposed marginal edges, whereby a quantity of the lubricant passingout over said exposed portions will be retained to prolong the period oflubrication of the packing flanges in their contact with the wall of themotor chamber.

3. A piston for the suction operated motors of windshield cleaners,comprising companion sections embracing a motor shaft therebetween, eachsection embodying a soft flexible cup packing member with its marginalpacking flanges arranged in proximity to the flanges of the companionsection, said cup members having side faces impervious to lubricant andmoisture and defining a compartment in the piston for the reception of aquantity of lubricant, the lubricant adapted to pass out onto thechamber walls across the opposed edges of the marginal packing flanges,said cup packing members being suificiently soft to impart to themarginal packing flanges flexibility for fluid, seal contact with thewall of the motor chamber, and metallic expander plates superimposedupon the packing flanges, said packing flanges being impervious to thelubricant whereby the lubricant which may collect intermediate theflanges and their expander plates will be retained thereby until free topass out of the compartment, therebytoprolongthe period of lubricationof the packing flanges in their contact with the wall of the motorchamber.

4. A piston for the suction operated moto'rs of member with its marginalpacking flanges. ar-

ranged in proximity to theflangesof the com-v panion section, said cupmembers defining a com- 1 partment in the piston for the reception ofaquantity of lubricant, the lubricant adapted to pass out onto thechamber wallsacrosslthe op.- posed, edges of the marginal packin flangeasaid.

cup packing members being sufficiently soft to impart flexibility to themarginal packing flanges and an active surface impervious to lubricantand moisture.

= ERWIN C. HORTON.

